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The indications and outcome of paediatric corneal transplantation in New Zealand: 1991–2003H Y Patel, S Ormonde, N H Brookes, L S Moffatt, C N J McGhee. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Br J Ophthalmol 2005;89:404–408. doi: 10.1136/bjo.2004.053116 NZNEB since 1991 has been the maintenance of a compre- Aim: To evaluate patient characteristics, indications, surgical hensive database, supported by New Zealand ophthalmic details, and outcome of paediatric keratoplasty in New surgeons, in which prospective data are collected on all aspects of corneal donation and transplantation. In this Methods: As part of a prospective longitudinal study, study the NZNEB database was analysed for the 13 year paediatric keratoplasty data collected by the New Zealand period 1991 to 2003 with respect to patient characteristics, National Eye Bank (NZNEB) was analysed for the 13 year indications, surgical details, and outcome of paediatric Results: During the study period the NZNEB supplied 2547corneas for keratoplasty, of which 65 (3%) were used for paediatric patients (14 years or younger). The 65 kerato- As part of a longitudinal, prospective study, the electronic plasties were performed in 58 eyes of 52 patients (66% male, records of the NZNEB were analysed for the 13 year period 34% female, mean age 10.6 years, SD 4.3 years).
1991–2003 with respect to demographics of recipients, Indications were classified into three groups: congenital indications, donor information, surgical details, and outcome (16%, n = 9), acquired non-traumatic (74%, n = 43), and acquired traumatic (10%, n = 6). Peters’ anomaly (7% of Data are entered into the computerised NZNEB database in total), keratoconus (67%), and penetrating trauma (8%) were a prospective manner by eye bank staff. Donor information is the most common indications in each group, respectively.
entered at the time of donor tissue procurement. Recipient 82% of keratoplasties with known outcome survived (clear and surgical information is collected from surgeons at the graft) 1 year postoperatively, 16% failed, and one patient time of operation. Follow up data are obtained at 1 and died. Keratoplasty for congenital indications had a lower 2 years postoperatively and are collected from surgeons by 1 year survival rate (78%) compared to acquired non- way of a mailed questionnaire sent out at the appropriate traumatic (85%) and traumatic (100%) indications, although Statistical analysis was performed in consultation with a the difference was not statistically significant (p = 0.65). 38% medical statistician from the epidemiology department of the of patients with known outcome had a 1 year postoperative University of Auckland. The SPSS V 12 software package was best corrected Snellen visual acuity (BCSVA) of 6/9 or better, used. Statistical methods were the Fisher’s exact test (when and 60% had a BCSVA of 6/18 or better. Visual outcome total number of observations were less than 20) and x2 was significantly better for acquired compared to congenital testing to compare proportions between groups, the Student’s t test to compare means between groups, and logistic Conclusion: Analysis of the NZNEB database provided regression modelling to identify factors associated with valuable information in relation to paediatric keratoplasty decreased keratoplasty survival. The level of statistical in New Zealand. In particular, this study highlighted an significance was p,0.05 unless stated otherwise. Visual unusually high prevalence of keratoconus as an indication for acuity was converted to a logMAR scale for the purposes of keratoplasty. In addition, a high 1 year survival rate and good visual outcome were identified, especially in cases ofkeratoplasty for acquired conditions.
RESULTSPatient demographicsDuring the 13 year study period the NZNEB supplied 2547corneas for keratoplasty, of which 65 (3%) were used for Paediatric keratoplasty is a difficult undertaking which patients within the paediatric age group (14years or presents a wide range of challenges preoperatively, younger). The 65 keratoplasties were performed in 58 eyes intraoperatively, and postoperatively.1–6 The presence of of 52 patients. The mean age of patients at the time of amblyopia, associated ocular pathology, and greater severity operation was 10.6 (SD 4.3) years, median age 12.0 years, of disease may significantly limit visual outcome.1–6 The and range 2 weeks to 14.0 years. The sex distribution was surgical procedure is technically more complex owing to the 66% (n = 34) male and 34% (n = 18) female.
decreased rigidity and increased elasticity of the infantcornea and sclera, the smaller size of the infant eye, the increased intraoperative fibrin formation and the positive The indications for paediatric keratoplasty are presented in vitreous pressure.1–6 Postoperative follow up and manage- table 1. The diagnostic classification system developed by ment may be more complicated, and graft rejection is often Stulting et al1 was used to facilitate comparison with other The New Zealand National Eye Bank (NZNEB), founded in Abbreviations: BCSVA, best corrected Snellen visual acuity; CHED, 1991, is the major supplier of donated ocular tissue for congenital hereditary endothelial dystrophy; ECD, endothelial cell transplantation in New Zealand. A standard protocol of the density; NZNEB, New Zealand National Eye Bank Paediatric corneal transplantation in New Zealand Table 1 Indications for paediatric keratoplasty Congenital corneal opacity not otherwise specified CHED, congenital hereditary endothelial dystrophy.
Table 2 Age and sex distribution for each diagnostic group published reports. Indications were classified into three indication in the less than 5 years age group and keratoconus groups: congenital, acquired non-traumatic, and acquired traumatic conditions. The congenital group accounted for16% (n = 9) of keratoplasties, the acquired non-traumatic group 74% (n = 43), and the acquired traumatic group 10% Keratoplasty was performed by 22 different surgeons in 10 (n = 6). Peters’ anomaly (7% of total, n = 4) was the most centres throughout New Zealand. Penetrating keratoplasty common indication in the congenital group, keratoconus was performed in 62 cases and lamellar keratoplasty in the (67% of total, n = 39) in the acquired non-traumatic group, remaining three cases. The indications for lamellar kerato- and penetrating trauma (9% of total, n = 5) in the acquired plasty were limbal dermoid, Peters’ anomaly, and congenital traumatic group. There were seven regraft procedures corneal opacification not otherwise specified. Donor informa- performed during the study period with original indications tion was available for all corneal tissue used with mean donor being keratoconus (n = 3), viral keratitis (n = 1), Peters’ age 44.4 (SD 18.0) years, median age 46.5 years, and range anomaly (n = 2), and penetrating trauma (n = 1). Kerato- 10–77 years. Mean endothelial cell density (ECD) was plasty was performed to improve visual acuity in 86% 3074 cells/mm2 (SD 386 cells/mm2), median 3065 cells/mm2, (n = 56) of cases, for tectonic reasons in 6% (n = 4), and and range 2578–4210 cells/mm2. The donor cornea button for a combination of reasons in 8% (n = 5).
was sutured to the recipient corneal rim with 10-0 Nylon The age and sex distribution for each diagnostic group are in 95% (n = 62) and a combination of Nylon and Prolene presented in table 2. There was no significant association in 5% (n = 3). An interrupted suture technique was used in between preoperative diagnosis and sex identified (congeni- 40% (n = 26), a single continuous suture in 26% (n = 17), tal, p = 0.16; acquired non-traumatic, p = 0.26; acquired and a combined interrupted/continuous technique in 34% traumatic, p = 0.43; regraft, p = 0.41, x2 test). The indications for different age groups (using stratified 5 year intervals) are Reported preoperative ocular conditions included corneal presented in table 3. Peters’ anomaly was the leading vascularisation in 19% (n = 12), previous intraocular surgery Table 3 Indications for keratoplasty for different age groups CHED, congenital hereditary endothelial dystrophy.
less than 5 years, 82%; 5–9 years, 78%; and 10–14 years, 83%.
Table 4 Outcome of keratoplasty 1 year postoperatively The differences between diagnostic groups (p = 0.65) and age groups (p = 0.51) were not statistically significant. There wasno statistical difference in survival rate based on suture method (p = 0.50) or type of postoperative medication used The most common reason for keratoplasty failure was irreversible rejection (10% of total, n = 5), followed by presumed primary tissue failure (defined as failure of the graft to clear) (4%, n = 2) and trauma (2%, n = 1). Episodes of reversible rejection were reported in 22% (n = 9) of casesthat survived 1 year postoperatively. Logistic regressionanalysis was performed in an attempt to identify factorswhich may be associated with decreased keratoplastysurvival. Factors included were pre-existing corneal vascular- in 14% (n = 9), a history of elevated intraocular pressure in isation, preoperative glaucoma, active inflammation at 6% (n = 4), and active ocular inflammation at the time of keratoplasty, small or large graft size, additional intraopera- operation in 9% (n = 6). Additional operative procedures tive procedures, immediate postoperative complications, and performed were anterior vitrectomy in 5% (n = 3), cataract episodes of reversible rejection. However, no individual factor extraction and intraocular lens insertion in 3% (n = 2), was identified from this analysis which resulted in a iridectomy in 2% (n = 1), and iridectomy plus synechiolysis statistically significant decrease in keratoplasty survival.
in 2% (n = 1). No significant intraoperative complications Best corrected Snellen visual acuity (BCSVA) was reported were reported. Early postoperative complications (within in 90% (n = 38) of cases that survived 1 year postoperatively 3 weeks) included wound leak in 5% (n = 3), wound (table 4). Of all paediatric keratoplasties, 38% (n = 18) infection in 2% (n = 1), corneal ulcer in 3% (n = 2), and achieved a BCSVA of 6/9 (20/30) or better and 60% early graft rejection in 2% (n = 1). Postoperative medical (n = 30) had a BCSVA of 6/18 (20/60) or better. Spectacles management consisted of Maxitrol (dexamethasone 0.1%, (n = 14) or contact lens (n = 2) were provided in 38% of neomycin 0.35%) in 60% (n = 39), prednisone acetate 1% cases. Visual outcome for each diagnostic group is presented plus chloramphenicol 0.5% in 32% (n = 21), with other in table 5. Visual outcome was significantly better for antibiotic-steroid combinations in 8% (n = 5).
acquired (mean logMAR 0.2, 6/10) compared to congenitalindications (mean logMAR 1.1, 6/75) (p = 0.03). Unfor- tunately preoperative visual acuity was not available for Outcome was evaluated 1 year postoperatively with follow up analysis as this was not recorded in the NZNEB database.
data available for keratoplasties performed from 1991 to2001. There were 58 keratoplasties during this interval withfollow up data available for 88% (n = 51). The remaining 12% (n = 7) were lost to follow up. The survival rate was New Zealand is a multicultural society with a population of determined by analysing the percentage of keratoplasties approximately four million, served by 110 ophthalmologists, that were surviving (clear graft) at 1 year postoperatively.
distributed over a geographical area slightly greater than the Eighty two per cent (n = 42) of keratoplasties survived, 16% United Kingdom. Over 200 keratoplasties are performed (n = 8) failed, and one patient died. Survival rates for annually in New Zealand and the NZNEB was established in different diagnostic groups were: congenital, 78%; acquired 1991 to support this demand. Over the 13 year study period it non-traumatic, 85%; acquired traumatic, 100%; and regraft was estimated that the NZNEB supplied at least 90% of all procedures, 80%. Survival rates for different age groups were: donated ocular tissue. Therefore, analysis of the NZNEB Table 5 Keratoplasty outcome for each diagnostic group and for regraft procedures Table 6 Indications for paediatric keratoplasty reported in the literature Paediatric corneal transplantation in New Zealand Table 7 Summary of published survival rates in paediatric keratoplasty database provides an accurate representation of corneal indications.1–4 12 13 The overall survival rate of 82% in this disease and keratoplasty in New Zealand.
The indications for paediatric keratoplasty vary signifi- reports.1–4 12 13 This may be because of the longer follow up cantly in the literature. Table 6 provides a comparison period at which survival rates were reported in some of the between this study and the major studies published over other studies.3 4 12 13 Another contributing factor may be the the past two decades. Most studies used the age criteria of high proportion of keratoplasties performed for acquired 14 years or younger. The proportion of keratoplasties non-traumatic indications. In concurrence with other pub- performed for congenital indications ranged from 14–64%, lished reports, a higher survival rate for acquired compared to for acquired non-traumatic 19–80%, and for acquired congenital indications was identified in this study,1–4 12 13 traumatic 6–29%.1–4 7 In this study, the proportion of although this did not reach statistical significance, possibly keratoplasties performed for acquired non-traumatic indica- owing to the small size of the congenital group. Of particular tions (74%) was significantly greater than that for congenital note, keratoplasty performed for keratoconus had an (16%) and acquired traumatic (10%) indications. This is in excellent prognosis with a 1 year survival rate of 90%.
contrast with the majority of published reports, in which In other published reports, several factors have been congenital indications contribute a significantly greater identified which increase the risk of failure in paediatric keratoplasty.1–4 14–19 Performance of an additional surgical Keratoconus was the most common acquired non-trau- procedure at the time of keratoplasty was most significantly matic indication in this study, accounting for 67% of all associated with a decreased survival rate, with other factors keratoplasties. This was notably higher than other published reported including preoperative glaucoma, associated ocular reports where keratoconus accounted for only 0–11% of conditions, and corneal vascularisation.1–4 14–19 In this study, paediatric keratoplasties, with post-infectious corneal scar- no factor was independently associated with a statistically ring the most common acquired non-traumatic indication significant increase in failure rate. However, the relatively reported in the literature.1–4 7 Similar to previous studies,1–4 7 small number of subjects limited this analysis. The influence the most common congenital indication identified in this of age alone on paediatric keratoplasty survival has been study was Peters’ anomaly followed by congenital hereditary evaluated with conflicting reports in the literature. Aasuri et endothelial dystrophy, and the most common indication in al4 identified a correlation between age under 5 years and the acquired traumatic diagnostic group was penetrating allograft rejection, and commented that this may be because of a more active immune system in younger patients. Other The notably high prevalence of keratoconus as an indica- studies, including this one, did not identify such an tion for paediatric keratoplasty reflects that which was identified by Edwards et al,8 who reported that keratoconus Poor visual outcome in a surviving keratoplasty (clear was the leading indication (45%) for keratoplasty in the adult graft) is well recognised within the paediatric age group and population in New Zealand, accounting for a significantlyhigher proportion of keratoplasties compared to other is most commonly a result of amblyopia, non-corneal ocular published reports. Ethnic differences in keratoconus pre- abnormalities, and postoperative astigmatism.1–4 17–19 In con- valence, severity, and rate of disease progression have been cordance with other published reports, this study identified a well recognised,9–11 and keratoconus is thought to be poorer visual outcome for congenital compared to acquired particularly prevalent in Maori and Pacific Island commu- indications.1–4 17–19 A higher prevalence of amblyopia and nities, which constitute a large proportion of the New associated ocular abnormalities in the congenital group has Zealand population. Edwards et al8 postulated that this high been cited as the reason for the less successful visual outcome prevalence, and possibly more rapid disease progression and in this group.1–4 17–19 We suspect that this may also be the case severity, has led to the uniquely high prevalence of in this study. Important considerations therefore are the keratoconus as an indication for keratoplasty in New timing of keratoplasty which should not be delayed Zealand. Similarly, this may explain the high prevalence of unnecessarily and the high priority of postoperative amblyo- keratoconus identified in this study. Over the past 4 years the NZNEB database has incorporated recipient ethnicity data to Analysis of the New Zealand National Eye Bank database further investigate the relation between ethnicity and has provided valuable information in relation to paediatric keratoplasty in New Zealand. In particular, this study Survival rates published by the foremost studies of identified an unusually high prevalence of keratoconus as paediatric keratoplasty are presented in table 7. Mean follow an indication for paediatric keratoplasty in New Zealand.
up generally ranged from 1–2 years and the reported survival High success rates at 1 year postoperatively, in terms of both rates ranged from 46–80%.1–4 12 13 Keratoplasty performed keratoplasty survival and visual outcome were identified, for congenital indications had a lower survival rate com- especially in cases of keratoplasty for acquired corneal pared to acquired non-traumatic and acquired traumatic 3 Cowden JW. Penetrating keratoplasty in infants and children. Ophthalmology The authors acknowledge the fundamental contribution to this 4 Aasuri MK, Prashant G, Gokhle N, et al. Penetrating keratoplasty in children.
research by Associate Professor Gillian Clover, PhD, FRACO, founder and first scientific director of the NZNEB; the key role of Dr David 5 Stulting RD. Penetrating keratoplasty in children. In: Brightbill FS, ed.
Pendergrast, clinical director; the chairman and trustees of the eye Corneal surgery: theory, technique and tissue, 3rd ed. St Louis: Mosby, bank for continued support, and past and present managers, 6 Vajpayee RB, Ramu M, Panda A, et al. Oversized grafts in children.
transplant coordinators, and scientific staff who have contributed to clinical and scientific aspects of the NZNEB over the past 13 years.
7 Dada T, Sharma N, Vajpayee RB. Indications for pediatric keratoplasty in Finally, the authors thank the ophthalmologists of New Zealand for their support and participation in the research and clinical activities 8 Edwards M, Clover GM, Brookes N, et al. Indications for corneal transplantation in New Zealand: 1991–1999. Cornea 2002;21:152–5.
9 Pearson A, Soneji B, Sarvananthan N, et al. Does ethnic origin influence the . . . . . . . . . . . . . . . . . . . . .
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14 Parmley VC, Stonecipher KG, Rowsey JJ, et al. Peters’ anomaly: a review of Correspondence to: Professor Charles N J McGhee, Department of 26 keratoplasties in infants. Ophthalmic Surg 1993;24:31–5.
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17 Waring GO III, Laibson PR. Keratoplasty in infants and children. Trans Am Acad Ophthalmol Otolaryngol 1977;83:283–96.
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19 Voolker-Dieben HJ, Kok-van Alphen CC, Lansbergen Q, et al. Different 2 Dana MR, Moyes AL, Gomes JAP, et al. The indications for and outcome in influences on corneal graft survival in 539 transplants. Acta Ophthalmol pediatric keratoplasty. Ophthalmology 1995;102:1129–38.

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